The field of the invention relates to liquid level detection.
Fluid level detection in motor vehicles has generally been accomplished manually by checking the appropriate dipstick. Since they too often are not checked at regular intervals, the fluid levels can become much too low before being detected. This can result in excessive wear to one or more vehicle parts or poor vehicle operation.
A number of devices here have been proposed for the automatic detection of low fluid levels so that a driver can be alerted before trouble occurs. One such device is disclosed in SAE publication 800127 by R. W. Tarpley et al. entitled Solid-State Automotive Liquid Level Sensing System. This article proposes the use of a positive temperature coefficient silicon chip having a current passed therethrough. U.S. Pat. No. 4,283,719 discloses a probe and a system for detecting the current passing therethrough.